Age-related macular degeneration (AMD) is a progressive neurodegenerative disease of late-onset that affects 25-30 million people worldwide. Vision screening and clinical characterization by ophthalmoscopic examination and fundus photography are the traditional measures used to identify and monitor AMD. While they are critical to characterizing disease status, these clinical assessments lack the sensitivity to monitor other aspects of functional visual impairment associated with disease progression such as dark adaptation; moreover, vision is minimally affected until advanced AMD. Consequently, there is a need for a functional assessment that effectively identifies and monitors early indications of disease progression prior to the onset of significant vision loss. This would be particularly useful as a potential clinical trial endpoint to investigate new therapeutics for patients with atrophic AMD. The objective of this study is to determine whether a new dark adaptation protocol can be used as a functional outcome measure to identify and monitor AMD progression. All enrolled participants will undergo the same assessment schedule, but they will be grouped into four categories (Groups 0-3) based on their disease severity at study entry. This comparison will investigate the sensitivity and reliability of the AdaptRx dark adaption protocol to detect disease progression (as a function of increased rod-cell impairment) over a 5-year time frame in participants with varying disease severity.